RE: TF Contender 60 build thread.
The original Contender was designed to be extremely fast to build. The original kit could have the "bare bones" assembled in 8 labor hours! The wing was flat because you could use 48" pieces for the wing spars and leading and trailing edges. That made it simple and light!. The thick wing made it stronger as well as made it have good low-speed handling. A lot of good ideas went into the original design.
The more-recent kit was re-engineered because all of the original tooling had been worn to the point of uselessness when Top Flight was acquired by Hobbico so many years ago.